Process of tanning hides, skins, and the like.



v UNITED STATES PATENT OFFICE.

WILLIAM G. ROACH, OF CINCINNATI, OHIO, AND ALBERT C.ROAGH, OF I-NEWPORT,KENTUCKY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE CINCINNATI CHROMELEATHER CORPORATION OF orno.

, Pnocsss OFY TANNING mam. I

To all whom it may-concern:

Be it known thatwe, WILLIAM G. Roaon, resi at Cincinnati, in the countyof Hamilton an State of Ohio, and ALBERT C. ROACH,

I ing into the fibers of the 7 be seen that the c omic oxid will also beuni- ,the ordinary two bath residing at Ne ort in the county of Cam belland Statd iif Kentucky, citizens of tlie United States, have inventedcertain new and useful Improvements in the-Process of Tanning Hides,Skins, and the Like, of which the following is a-specification.

The object'of our invention is to provide a piocess for the metallictanning or tawing of 'des which produces a leather having substantiallythe same capacity for finishing,

'working, or use as bark-tanned leather while retaining the to hness anddurablity of the metallictanned eather. It consists, broadly speaking,in introduces in a substantially inactive chemical state substances,containing tanning matter adapted to be released by reactionbetw'een'smdcompounds and then establishing a condition under which said reactionwill take place. We

prefer; to employ chromic acid as the substance contammgh the tanningmatter and introduce it into t e hide in substantially the same form andmanner as in the first bath of rocess. After the hide has becomethoroughly soaked and impregnated with the chromic acid we introduce areducing agent, such as glucose, which does not act at onceupon thechromic acid, but is what may be termed chemically inactive for the timebeing toward said acid. When the hide has become thoroughly soakedandimpre ated with the glucose, it will be seen that t e chromic acid andglucose are intimately and uniformly associated together and with thefibers of the hide Thus, in effect, we bring each molecule of thechromic acid into intimate association with its molecule of glucose onthe particular fiber upon which their product is to .act before saidproduct is released. Under these circumstances when the: reaction doestake place the chromic oxid is deposited directly and immediately uponthe hide fibers. 'As the chromic acid and glucose are uniformlydistributed thro bout the hide fiber, it wil I Specification of LettersPatent. Application-filed larch 4.1904. Serial No. 196.667.

fibers will COMPANY, OF CINCINNATI, OHIO, A

HIDES. SKINSQAND THE LIKE. Y

Patented n... so, 1900.

formly deposited thereon and the interior receive their dueproportion ofthe oxid.

In practice for one hundred poundsof hides we employ as the first bathsix pounds of bichromate of potash or soda, four pounds of alum, four tosix ounds of common salt, twelve ounces of sulfiiric acid, twenty ouncesof hydrochloric acid, sixty gallons of water. The hides tobe treated arepre ared in the usual manner for tanning and allowed to soak in thisbath until thorou hly im regnated with the chromic acid. glhls wilordinaril take from twelve to ei hteen hours, depen ing u on the weightan thickness of the hides. he hides are then removed from the bath,sliked, set out, and hung up until about three-fourths of the moisturetherein has evaporated. When in this state, the hides are spread out andpainted on both sides with a solution of glucose and packed in piles forfrom three to six hours to allow the glucose to soak in and becomeuniformly distributed throughout the hide. The glucose solution maycontain from fifteen to fifty per cent. of glucose dissolved in water.If applied under ordinary atmos heric temperatures, there will besubstantially no immediate reaction between the glucose and chromicacid, they being under the conditions ap lied in an inactive statetoward each other. husthe lucose will soak into the hide and thorou hIyand uniforml associate itself with the c omic acid and 'de fibers beforeany reducing action takes place. By painting the glucose solution ontothe hide possible contact between the chromic acid in the hide and theglucose solution from which the painting-supply is taken is prevented.

To prevent the glucose from so in warm weather, we use for, say, threegal one of water, about a half-pound of'quassia chips, and, say, a halfan ounce of carbolic acid. The uassia chips are boiled with the waterand t e carbolic acidadded, and into this is stirred the glucose to makeup the necessary strength of the solution.

' In the chromic-acid bath a small excess of sulfuric and hydrochloricacid tends to has-- ten the reduct1on.- a larger excess of acid be used,the reduction will t e place in a prop y cess of acid is not enough tocause the reducglucose is uniformly distribp ose. the afourth of t 4think a slower.

condition under whic portionately shorter time. Thus if itis desired tohasten the reduction an excess of acid, referably sulfuric acid, may beembut care should be taken that the ex tion before the uted through thehide or cause the acid to injuriously affect the hide fiber. We preferto use glucose as the reducing agent.

All organic substances have more or less reducingaction on chromic acid,and we at an organic compound will generally be found preferable toemploy as a reducing a ent, since their action is generally However,even an inorgamc reducmg agent may be employed if the proper conditionsare 0 tained for preventing immediate reduction. After the hides havebeen uniformly inpregnated with the chromic acid and glucose a conditionis established under which the reaction between said substances takesplace to release the chromic oxid or tannin substance.

This condition may be established in a number of wa s; but we prefer touse a bath of hot grease or this After the hides have been treatedlucose solution and about one e moisture has evaporated therefrom theyare immersed in a bath of hot grease, the proportions of-the in redientsof this bath bemg dependent upon t e purposes for which the leather isto be used.

For the production of a suitable soleleather we make up a bath asfollows: one hundred pounds stearic acid, twelve and onehalf poundscarnauba-wax, six and onefourth pounds Vaseline, six and one-fourthpounds beeswax. This grease-bath is reduced to a liquid and kept at atemperature between and centigrade, and the hides are suspended in thisbath until the grease has thoroughly enetrated the thickest parts of thehide. his will be found to take only a comparativel short time, an houror more being all t at is necessary. The effect-of the hot ease is toestablish a the chromic acid is thoroughly reduced and at the same timethe hide is thoroughly filled with grease. For sole-leather the hidesare then rolled and finished in the usual way. For harness-leather theproportion of Vaseline in the stufling-bath must be increased to makethe leather as soft as wanted-say twenty-five pounds of vaseline insteadof six and a uarter pounds, as above stated. To obtaint e best results,the glucose should be kept at about 50 centigrade.

While our process attains its greatest utility in tanning thick or heavyhides, it may also be used to advantage for thin hides and will be foundto produce a high grade of uniformly-tanned leather.

We claim as our invention- LgThBSPIOCGSS of tanning hides which coned tobe released by reaction between said substances, and then appl lg heatto establish a condition under w 1c will take place, substantially asspecified.

3. The process of tanning hides which consaid reaction sists inintroducing into the fibers of the hide,

in a substantially inactive chemical state, substances containingtanning matter adapted to be released by'reaction 'between'saidsubstances, and then subjectin the hide to a bath of hot grease toestablis a condition under which said reaction will take place,substantially as specified.

4. The process of tanning hides which consists in introducing areducible metallic substance into the fiber of the hide; thenintroducing a reducing agent into the hide fiber in a substantiallyinactive chemical state to ward said metallic substance; and thenestablishing a condition under which reduction will take place,substantially as specified.

5. The process of tanning hides which consists in introducing areducible metallic substance into the fiber of the hide; thenintroducing a reducing agent into the hide fiber in a substantiallyinactive chemical state to ward said metallic substance; and thenapplying heat to establish a condition under which reduction will takeplace, substantiallyas specified.

6. The process of tanning hides which consists in introducing areducible metallic substance into the fiber of the hide; thenintroducing a reducing agent into the hide fiber in a substantiallyinactive chemical state toward said metallic substance; and thensubjecting the hides to a bath of hot grease toestablish a conditionunder which reduction will take place, substantially as specified.

7. The process of tanning hides whichbonsists in subjecting them to abath of chromic acid; then to that of an organic reducingagent,substantially inactive chemically to ward the chromic acid; and thenestablishing a condition under which reduction will take place,substantially as specified.

8. The process of tanning hides which consists in subjecting them to abath of chromic acid; then to that of an organic reducing agent,substantially inactive chemically to ward the chromic acid; and then toa bath of hot grease to cause the reduction, substantially as specified.

9. The process of tanning hides which con- ICC IIO

sists in subjecting them to a bath of chromic acid; then to that of asolution of glucose under conditions in which the chromic acid andglucose are chemically inactive; and then establishing a condition underwhich the chromic acid is reduced by the glucose, sub} acid, thenpainting the hides with a reducing agent chemically inactive toward thechromic acid, and then establishing a condition under which reductionwill tially as specified.

11. The recess of tanning hides which consists in su jecting them to abath. of chromic acid, then painting the hides with a solution ofilucose, and then subjecting them to a bat of hot grease, substantiallas specified.

WILLIAM ROACH.

ALBERT O. ROACH.

' Witnesses:

GLENA. PRITOHARD, I O. M. ROGERS.

take place, substan- I

